Device for keeping constant the terminal voltage of sources of current



Aug. 1, 1933. L.- KOROS 1,920,569 DEVICE FOR KEEPING CONSTANT TERMINALVOLTAGE OF SOURCES dF CURRENT Filed Nov. 11, 1929 Fig I wvw I w .i q n IV3 awn/011' '14 laofi/aw/fahl's Patented Aug. 1, 1933 DEVICE FOR KEEPINGCONSTANT THE TER- MINAL VOLTAGE OF SOURCES OF OUR- RENT LadislausKiiriis, BerlinsTempelhof, Germany, assignor to N. V. Stabilovolt,s-Gravenhage,

Netherlands Application November 11, 1929, Serial No. 406,486, and inHungary November 12, 1928 5 Claims. (Cl. 171-312) In order to maintainthe terminal voltage of sources of current at a constant value,particularly of such sources which possess a relatively high innerresistance, according to the invention a glow cathode discharge tube(electric arc) filled with gas is connected in parallel to the terminalsof the sources of current. It has already been proposed to employ aglow-lamp for suppressing fluctuations of voltage, however, theapplication of glow cathode tubes. ofiers advantages in various respectsopposite from that arrangement. The glow-cathode discharge tubes areknown per se and up to the present they were used for redressing strongcurrents only. The arrangement of a glow-lamp mentioned can be employedonly with voltages above '70 volts, while according to the invention itbecomes possible to maintain even the smallest voltage at a constantvalue. It is thus easily possible, to keep also the Voltage supplied tothe heating wires of electronic tubes, amounting to 4 volts andthereabouts, at a constant value. In addition the device according tothe invention shows the advantage, that the limit of the intensity ofcurrent is not limited towards high figures, as such is the case withglow-lamps, since the discharging distances of the glow cathodes can beloaded substantially higher than glow-lamps. Besides. the glowcathodedischarge tubes employed possess such a high efiiciency in smoothing thevoltages, that,

the customary condenser employed for bridging the terminal voltage canbe dispensed with.

A further advantage is to be seen in the fact that the working pressureof a glow-cathode discharging tube will change accordingto the extent ofheating, so that by controlling the heating effect the same dischargingtube may be used for keeping constant different voltages or the avail-.

able discharging tube may be accurately adjusted to the voltage requiredby the consumer, respectively. This latter feature is of specialimportance, since it is often diflicult to produce on a large scale glowcathode discharging tubes for an accurately predetermined voltage. Amode of execution of thearrangement according to the invention isillustrated in-the drawing by way of example.

Figure 1 is a diagram of a suitable connection. Figure 2 is anotherdiagrammatic view. Figure 3 is a diagrammatic view of a modifica- .tionof Figure l.

Referring now to Figure 1 the source of curren having a relatively highinner resistance consists of the transformer l, 2, 3 connected to thealterhating current network, the primary winding of said transformerbeing connected to an alternating current network while two voltages aredrawn from the secondary side, one of which is redressed for theconsumer and the other one is to serve for heating the glow cathodedischargingtube. The winding 3 serves for this latter pur-.

pose. 1

This arrangement will be given the preference in most instances, sincethe network current can be directly used for heating purposes, in thatan indirectly heated electrode of a high heat-inertia is employed, andin addition by this method the alternating current components of theheating circuit will not be transferred to the circuit of the consumer.To the secondary winding 2 is connected the rectifier or redresser 4 anda filter circuit known per se, consisting of the capacities 5, 7 and theinductivity 6. In order to maintain the voltage at the terminals 8 and9, to which the consumer is supposed to be connected, at a constantvalue'independently of the changes of load, a glow cathode dischargingtube 10 filled with gas is inserted between said terminals, the cathodell of which tube is heated by the heating winding 12 connected to thesecond secondary winding of the transformer by way of the regulatingresistance 13.

As anincrease of the load, for instance, from 2 milli-amperes to 2amperes in the glow cathode discharging tube will involve only a veryslight change of voltage, for instance of 5 per cent, it follows, thatthe discharging tube exerts a powerful action of smoothing the voltage,assuch is characteristic of a condenser of very large capacity. For thatreason the discharging tube is also excellently adapted for doing thework of the condenser 7, and so thelatter may be dispensed with withoutany. injurious consequences.

As the glow cathode discharging tube 10 possesses an incliningcharacteristic, an ohmic resistance 14 is connected in series with saidtube.

For this case Figure 2 illustrates more fully the .apply for saidresistance. As the negative and positive characteristics will sum up inthe total circuit, there follows the sum R resistance shown in brokenlines in Figure 2. It is thus possible If a resists its with a suitableselection of the positive resistance to obtain at the terminals 8 and 9any desired course, that is to say also an alternating currentresistance, equal to zero.

As discharging tubes having two electrodes will be diflicult to beignited at a reduced voltage, auxiliary electrodes supplied with highvoltage may be arranged within the discharging tube for facilitating theignition, in order to ionize the gas filling by means of these auxiliaryelectrodes. It is also possible to simultaneously heat the auxiliaryelectrodes by heating the main cathode.

A preferable arrangement is shown by Figure 3, the tube 10 having anauxiliary electrode 15 provided with a heating winding 16 energized bythe coil 3 of the transformer, through a regulating resistance 17.Preferably, a resistance 18 is interposed between the electrode 15 andthe line so that the voltage of the auxiliary and main electrodes of thetube will be the same. This auxiliary electrode is able to start thedischarge in the tube so that the gas therein will be ionized to insurea discharge between the main electrodes upon increase in voltage.

I claim: I

l. A device for maintaining uniform potential difference between twoconductors carrying continuous current and comprising an arc dischargegap and a resistance bridged in series between said conductors, saiddischarge gap having a negative voltage characteristic and theresistance having a positive voltage characteristic balancing thenegative voltage characteristic of the discharge gap whereby thealgebraic sum of the effects of such characteristics is zero.

2. A device for maintaining uniform potential difference between twoconductors carrying continuous current and comprising a discharge gapbetween the terminals of which discharge takes place as an arc and aresistance bridged in series between the conductors, said discharge gaphaving a negative voltage characteristic and the resistance having apositive voltage characteristic; said resistance being variable wherebythe positive voltage characteristic of the resistance may be caused tobalance the negative voltage place as an arc, and an ohmic resistancebridged in series between the conductors, said discharge gap having anegative voltage characteristic and the resistance having a positivevoltage char acteristic, said resistance being variable whereby the,positive voltage characteristic of the resistance may be caused tobalance the negative voltage characteristic of the gap and the algebraicsum of the effects of such characteristics may be caused to be zero.

4. A device for maintaining uniform potential difierence between twoconductors carrying continuous current and comprising an arc dischargegap and a resistance bridged in series between said conductors, saiddischarge gap having a negative voltage characteristic and theresistance having a positive voltage characteristic balancing thenegative voltage characteristic of the discharge gap whereby thealgebraic sum of' the effects of 'such characteristics is zero, saiddischarge gap having spacedelectrodes, and means independent of saidconductors for heating the field surrounding said electrodes.

5. A device for maintaining uniform potential difference between twoconductors carrying continuous current and comprising an arc dischargegap and a resistance bridged in series between said conductors, saiddischarge gap having a negative voltage characteristic and theresistance having a positive voltage characteristic balancing thenegative voltage characteristic of the discharge gap whereby thealgebraic sum of the effects of such characteristics is zero, saiddischarge gap having spaced electrodes, and means independent of saidconductors for heating the field surrounding said electrodes, saidheating means including a regulating resistance.

LADISLAUS KtiRijs.

